Extension-scaffold



2 Sheets-Sheet 1.

(No Model.) 7

A. DOOLITT'LE. EXTENSION SGA'FFOLD.

No. 551,434. Patented Dec. 17, 1895.

2 Sheets-Sheet 2.

{No Model.) 7 Y A.'DO0LITTLE.

EXTENSIONYSGAFFOLD. No. 551,434. Patented Dec. 17, 1895.

UNITED STATES PATENT Orricn.

ASA DOOLITTLE, OF ST. LOUIS, MISSOURI.

EXTENS'lON-SCAFFOLD.

SPECIFICATION forming part of Letters Patent No. 551,434, dated December 17, 1895. Application filed February 25, 1895. Serial No. 539,685. (No model.)

To all whom it may concern.-

Be it known that-I, ASA DOOLITTLE, a citizen of the United States, residing at St. Louis, in the Stateof Missouri, have invented certain new and useful Improvementsin Extension-Scaifolds, of which the following is a specification, reference being had therein to the accompanying. drawings.

This invention relates to certain new and useful improvements in extension-scaffolds.

The object of my improvements is to provide a universally-extensible scaifoldone that may be extended in length and width as well as height, and be readily adjusted according to circumstances and the position in which it is to be used.

To this end my improvements have refer ence to a. clamp especially adapted for this purpose; have reference to certain peculiarities of construction in the clamp and its accessories, and have reference to a separate platform for the workman and the material he is using in his work.

In the accompanying drawings, on which like reference letters indicate corresponding parts, Figure 1 represents a perspective view of a portion of a scaffold exemplifying my improvements Fig. 2, a perspective of a corner of the scaifold secured by my form of clamp; Fig. 3, an end view and sect-ion of the scaffold located in position for work on the adjoining wall shown in section; Fig. 3, a detail of two spanning-pieces clamped together; Fig. 4, a face detail view of my clampingblock; and Figs. 5 and 6, details of the eccentric cam and friction-plate, respectively.

The letter A represents a platform supported at an adjustable height parallel to the wall being built; On this platform are deposited the bricks or other. material to be used in construction-work. At a'convenient height below the first platform isa secondary platform 13 and adjacent to the wall, on which the workman stands while using the material deposited on'the main platform. In order to support these platforms and vary their-height from the ground I provide a series of trestles which are set edgewise to the wall and are adj ustable as to height. Each trestle is formed of two lower legs D D securely clamped to upper legs or posts D" D by a clamping device to be presently described. A cross-piece O caps the upper legs and supports the platform A, on which the building material rests. The weight of the material is thus carried directly by the ends of the upper posts or legs.

To stiffen the trestles longitudinally 1 provide the spanning-pieces E, which fit upon the inside, preferably, of the posts D and below the cap-piece C. A clamping device securely fastens all the piecess meeting together at this point on the trestle. This clamping device consists of a block or support F of any suitable width and length, and which forms a support for one or both of the cams used. This block is applied directly to the surface of the timber, and while it enables the clamping device to be used where other clamps cannot be it also serves to enable the two cams to be used independently of each other, and enables either one to be used for tightening or loosening the connection. When the upper end of the block is brought in con tact with the cross-timber the clamp can be used to clamp timbers together that extend at right angles to each other. On each side of the block is pivoted an eccentric cam G having a handle II and a groove g, about which passes a connection of twisted wire or other suitable material, which is tightened by operating the cam-eccentrics. One eccentric only maybe used, if desired. Fig. 5 shows the inside view of one of said eccentrics, and

Fig. 4 a corresponding edge view mounted on the block or support.

It will be understood that when the handle I-I rotates the eccentric on its center bolt I the cam portion of the disk G is brought from one side to the other of the center and acts to tighten or loosen the wire connection. This connection may be arranged to pass from the eccentric on one side, around the posts adjusted to their properheight and then around the eccentric on the other side. Vhen the handles are in their dotted position the con nection is loose and the adjustment of the posts past each other is readily made. \Vhen the handles are drawn down, as shown in full lines, the connection is tightened and securely clamps the posts together. Fig. 2 shows a crossed arrangement, and Fl 1 and 3 show a straight form. V

In order to take up slack in the connection due to wear or shrinkage of the wood, a spacing-plate J is fastened to theoppositeside of the post from the clamping-block. This plate is corrugated transversely,or otherwise adapted to separate the loops of wire passing around the posts from one side, to the other. A further function is the bracing effect secured by maintaining the wires a greater distance apart than the diameter of the eccentric.

The clamping device maybe secured to'the top of the post D on one or bot-l1 sides of the trestle, but is preferably loose when used at the bottom of the post.

The platform 13 is supported by a crossbar K, Figs. 1 and 3, which may be permanently secured at one side of the trestle to the post 1), as its height is permanent with regard to the platform A, and projects toward the wall to carry the platform B directlyalongside. The other end reacts against the brace L. It stiffens the trestles edgewise,,anda further bracing effect is secured by the cross-braces L L screwed or otherwise detachablysecured to the posts D, as shown in Fig. '3, and forming shoulders at their upper ends to support the spanningepieces E. The latter pieces may he, therefore, comparatively light, since they have only to resist longitudinal strain, unless extra cross-pieces be placed thereon parallel to the cap-pieces O. Any degree, of strength may be secured byplacing the trestles .at cor: responding distancesapart.

'When a long platform is desired,-the spanning-pieces arelapped by each other at their ends, andthe clamping device securely fastens them together or to the posts .and cap pieces as they rest upon the shoulderedbraces L. (See Fig. 3.)

Referring to Fig. 4, it will be seen thatthe binding-wire cannot slip from the eccentrics, as it is inside of the handles and has a friction-plate M on the side of the block, which also serves to retain the handlein its clamping position by means of depressions .and ridges formed in one portion of it, which are engaged by matching projections on the handle II when such handle is in itslower position. The strain of the binding connection is, however, practically through the bolt I when the cam portion is thrown to its tightened position. There is, therefore, little strain upon the handle to displace it.

In Fig. 2 is shown a pin 0 projecting from the side of the cap-piece over which the binding connection may be passed instead of crossing above the cap-piece.

I .do not limit myself to any special construction or arrangement, as I wish to be understood as laying broad claim to thisinvention as hereinbefore described.

This scaffold is especially adapted to bricklayers, masons, plasterers, painters, and carpenters, and, in fact, to those using a scaffold in places where it is necessary to reach various heights, such as plastering ceilings and walls, and where the ground may be uneven, such as in cellars or Stairways, in which latter places the adjustable legs of the scaffold maintain the platformslevel and secure steady footing by their independent adjustment. In plastering ceilings, for instance, the trestles may be extended edgewise to make a wider platform-support, and several may be clamped together to make any reasonable size of platform, as desired. For some purposes and trades it may not be required to extend the trestles edgewise in order to widen the platform, and I do not, therefore, limit myself to the exact construction herein shown.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A clamp consisting of a block, one or more cams mounted thereon, a handle for each cam, and means applied to the block for holding the handles in any desired position; combined with a flexible connection secured to-the cams, .and .a spacing plate applied to the opposite side of the timber from the block,

I substantially as described.

2. In aclamping device, a supporting block and two independentv cams mounted thereon, combined with a flexible connection connected to both cams, as described.

3. The combination with two or more adjustable pieces, of a pair of cam eccentrics, a

support therefor, a binding connection embracing said pieces and eccentrics, acorrugated spacing plate for said binding connec tion, .and a friction plate to retain the eccentrics carried by. said block in tension position.

4. The combination with two or more adj ustable piec.es,.of a. detachable block, an ecoentric disk mounted on each side of said block having a handle,a friction plate for .said handled disk mounted on said block, and

a binding connection looped over each disk between the handleand plate, andalso around said adjustable :pieces.

.5. In a clamp, a supporting :block, a rod mounted upon the -block,.a cam andan operating handle at each end of the rod, anda flexible connection connected to the cams,.con1- bined with holding'plates applied to the edges of the block for holding the handles, substantially asshown.

G. In a clamp, a supporting block, a rod mounted thereon, and a cam and ahandle at each end of the rod, the handles being provided with teethon their inner sides, combined with ratchet holding plates applied to the edges of the block, .and a flexible connection that forms loops around the cams, substantiallyas described.

7. In a scaffold, the uprights, the'horizontal pieces applied thereto, and the cap piece .extendinghorizontally across them, combined with a block that isappliedto the side of the upright, a rod mounted on the block, and provided with a cam .ateach end, and a flexible connection that is twine'd around the said timbers of the scaffold and connected to the two cams, substantially as set forth.

8. In a scaffold, the cap piece, provided with pins which project from its sides; the uprights, and the horizontal pieces secured thereto, combined with a supporting block that is applied to the side of the upright, a rod mounted on the block, a cam applied to each end of the rod, toothed plates applied to the edges of the block for holding the cams after they have been tightened, and a flexible connection that is twined around the horizontal pieces and up over the pins, substantially as specified.

9. In a clamping device, a movable block or support, one or more cams rotatably mount: ed thereon, and a flexible binding connection adapted to loop around said cam or cams and the pieces to be clamped together, substantially as described.

In testimony whereof I aifix my signature in presence of two Witnesses.

ASA DOOLITTLE. Witnesses M. JAooBY, H. M. PLAISTED. 

